Mapping Question

martyb555 · **Joined:** Wed Aug 08, 2007 3:08 pm **Posts:** 4

Mapping question from newbee,

I have the following interest rate table (note: a tier is associated with a min balance);

I have successfully mapped an InterrestRate class to an individual row with this mapping;

Code:

<class name="InterestRate" table="INTEREST_TIERS" >
        <composite-id>
            <key-property name="companyId" column="COMPANY" />
            <key-property name="tier" column="TIER" />
            <key-property name="effectiveDate" column="EFFECTIVE_DATE" type="date"/>
        </composite-id>    
        <property name="throughDate" column="THROUGH_DATE" type="date"/>
        <property name="interestRate" column="INTEREST_RATE"/>
        <property name="yield" column="YIELD"/>
</class>

I now want to create a class MonthlyInterestRates that contains a List of InterestRate objects so I can handle the 3 tiers as one persistent object.

Java Code For MonthlyInterestRates....

Code:

public class MonthlyInterestRate implements java.io.Serializable {

    private String companyId;
    private Date effectiveDate;
    private List interestRateTiers;  //list of InterestRate objects
    ....
    ...
}

I have having a difficult time in figuring out how to map this, any ideas?
The way I would want this to work would be that when I save the MonthlyInterestRate object, the 3 database rows would appear in the database.

Thanks,
Marty

sracharla · **Posted:** Thu Aug 09, 2007 12:39 am

Use bag mapping. so when you save Monthly Interest rates it also saves Interest rates.

mkarami · **Posted:** Thu Aug 09, 2007 3:22 am

Maybe Something similar to the the following:

Code:

<class name="InterestRate" table="INTEREST_TIERS" >
        <composite-id>
            <key-property name="companyId" column="COMPANY" />
            <key-property name="tier" column="TIER" />
            <key-property name="effectiveDate" column="EFFECTIVE_DATE" type="date"/>
        </composite-id>   
        <property name="throughDate" column="THROUGH_DATE" type="date"/>
        <property name="interestRate" column="INTEREST_RATE"/>
        <property name="yield" column="YIELD"/>
        <many-to-one name="monthlyinterestrate"
            insert="false"
            update="false" 
            not-null="true">
        <column name="companyId"/>
        <column name="effectivedate"/>
        </many-to-one>
</class>

<class name="MonthlyInterestRate" table="monthlyinterestrate" lazy="true">
    
    <composite-id>
        <key-property name="companyId"/>
        <key-property name="effectivedate"/>
    </composite-id>
                
    <bag name="interestratetiers"
            fetch="join" 
            inverse="true"
            cascade="save-update">
        <key>
            <column name="companyId"/>
            <column name="effectivedate"/>
        </key>
        <one-to-many class="InterestRate"/>
    </bag>
    
</class>

martyb555 · **Joined:** Wed Aug 08, 2007 3:08 pm **Posts:** 4

Thank you very much for your reply.
There is one issue though. there is no monthlyinterestrate table in the legacy database. The MonthlyInterestRate object is an encapsulation of the three InterestRate records. Is that possible? Any Ideas?

mkarami · **Posted:** Fri Aug 10, 2007 2:38 am

Hi,
I am not sure if I understand it correctly, but how would you than keep track of MonthlyInterestRate data? I mean where do you keep the relationship between companyID's and interestRateTiers values? I assume there needs to be a table that keeps track of the relationship between sets of interest rates and their companyId. To give an example:

Code:

<hibernate-mapping package="eg">

    <class
        name="user"
        table="user">

        <id name="id"  column="user_ID">
            <generator class="native"/>
        </id>

        <property name="name" column="NAME" not-null="true"
            unique="true"/>

        <bag name="interestRateTiers" inverse="true" cascade="all">
            <key column="user_ID"/>
            <one-to-many class="InterestRate"/>
        </bag>
    </class>

<class
        name="InterestRate" table="InterestRate"
        dynamic-update="true">

        <composite-id>
            <key-property name="companyId" column="COMPANY" />
            <key-property name="tier" column="TIER" />
            <key-property name="effectiveDate" column="EFFECTIVE_DATE" type="date"/>
        </composite-id> 

        <property name="throughDate" column="THROUGH_DATE" type="date"/>
        <property name="interestRate" column="INTEREST_RATE"/>
        <property name="yield" column="YIELD"/>

        <many-to-one
            name="user"
            column="user_ID"
            not-null="true"/>
    </class>
</hibernate-mapping>

martyb555 · **Joined:** Wed Aug 08, 2007 3:08 pm **Posts:** 4

The relationship is stored in the same table. The table layout and sample data are in the initial post above. In this case both objects come from the same (legacy) table. In the sample data above there is only one company shown (902). The data shows that for each month there is a new set of tiered interest rates entered. From an object oriented perspective the monthly object contains a collection of interest rates keyed by tier.